de.aristaflow.adept2.util

Class ArrayTools

java.lang.Object

de.aristaflow.adept2.util.ArrayTools

public final class ArrayTools
extends java.lang.Object

Utility class for array-related helper methods.

Author:

Patrick Schmidt

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ArrayTools.ArrayWrapper<T> A wrapper for arrays that provide a useful (i. e. deep) ArrayTools.ArrayWrapper.equals(Object), ArrayTools.ArrayWrapper.hashCode() and ArrayTools.ArrayWrapper.toString().

Method Summary

Modifier and Type	Method and Description
static <T> T[]	after(T[] arr, int index) Gets an array containing all elements of the designated array after (and without) the designated index.
static <T> T[]	before(T[] arr, int index) Gets an array containing all elements of the designated array before (and without) the designated index.
static boolean	contains(int[] arr, int elem) Gets whether the designated array contains the designated integer element.
static <T> boolean	contains(T[] arr, T elem) Gets whether the designated array contains the designated element.
static <T> T[]	join(T[]... arrays) Returns a new array of the same type as all input arrays filled with their joined content.
static <T> T[]	removeElement(T[] arr, int index) Removes the element at the designated index from the designated array.
static <T> T[]	reverse(T[] array) Reverses the entries in the designated array and returns the very same array afterwards.
static <T> T[]	toArray(java.util.Collection<T> coll, java.lang.Class<T> componentType) Returns the content of the given collection in a newly created array with the given component type and the size of the collection.
static <T> T[]	toArray(T... content) Creates an array of the designated content.
static <T> java.util.List<T>	toList(T[] array) Returns the content of the given array in a newly created (array) list.
static <T> java.util.Set<T>	toSet(T[] array) Gets the content of the designated array in a newly created set.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

toArray

public static <T> T[] toArray(T... content)

Creates an array of the designated content. This allows for easy null and singleton array behaviour.
Note that null behaviour depends on how the method is called, while (T) null returns an array with a null element, (T[]) null returns null (and no array).

Parameters:

content - The content of the array to return.

Returns:

An array containing the designated content or null.

reverse

public static <T> T[] reverse(T[] array)

Reverses the entries in the designated array and returns the very same array afterwards.

Type Parameters:

T - The type of the elements of the array to be reversed. Note that this cannot be a simple type.

Parameters:

array - The array to reverse the order of.

Returns:

The array having its order reversed. The return value can be ignored since the order is changed via side-effects on the original array.

join

public static <T> T[] join(T[]... arrays)

Returns a new array of the same type as all input arrays filled with their joined content. Only use this method where it's not possible to use Lists instead.

Type Parameters:

T - component type of the arrays

Parameters:

arrays - the arrays to be joined

Returns:

new array filled with the joined content of the specified arrays

toArray

public static <T> T[] toArray(java.util.Collection<T> coll,
                              java.lang.Class<T> componentType)

Returns the content of the given collection in a newly created array with the given component type and the size of the collection.

Type Parameters:

T -

Parameters:

coll - the collection whose elements should be copied to a new array

componentType - the component type of the array to be created

Returns:

toList

public static <T> java.util.List<T> toList(T[] array)

Returns the content of the given array in a newly created (array) list.

Parameters:

array - an array

Returns:

an array list with the same content as the given array

toSet

public static <T> java.util.Set<T> toSet(T[] array)

Gets the content of the designated array in a newly created set. This allows for efficient comparisons, e. g. Set.contains(Object).

Parameters:

array - The array which to get as (Hash)Set.

Returns:

A (Hash)Set containing the elements of the designated array.

contains

public static boolean contains(int[] arr,
                               int elem)

Gets whether the designated array contains the designated integer element.
Note that this simply iterates the array so use it carefully to avoid runtime complexity. For instance using it within an iteration multiplies runtime complexity.

Parameters:

arr - The array which to check for whether it contains the designated integer element.

elem - The integer element which to check for whether it is part of the designated array.

Returns:

Whether the designated integer element is part of the designated array.

contains

public static <T> boolean contains(T[] arr,
                                   T elem)

Gets whether the designated array contains the designated element. The element can be null.
Note that this simply iterates the array so use it carefully to avoid runtime complexity. For instance using it within an iteration multiplies runtime complexity.

Parameters:

arr - The array which to check for whether it contains the designated element.

elem - The element which to check for whether it is part of the designated array. This can be null.

Returns:

Whether the designated element is part of the designated array.

removeElement

public static <T> T[] removeElement(T[] arr,
                                    int index)

Removes the element at the designated index from the designated array. If the designated index is outside the designated array, the array will be returned without changes.

Parameters:

arr - The array from which to remove an element.

index - The index of the element which to remove.

Returns:

The designated array without the element at the designated index.

before

public static <T> T[] before(T[] arr,
                             int index)

Gets an array containing all elements of the designated array before (and without) the designated index. If the designated index is <=0, an empty array will be returned, if the designated index is bigger than the designated array, the array will be returned without changes.

Parameters:

arr - The array from which to remove elements.

index - The index of the first element that is not part of the returned array.

Returns:

The designated array without the elements at and after the designated index.

after

public static <T> T[] after(T[] arr,
                            int index)

Gets an array containing all elements of the designated array after (and without) the designated index. If the designated index is >=arr.length, an empty array will be returned, if the designated index is <=0, the array will be returned without changes.

Parameters:

arr - The array from which to remove elements.

index - The index of the last element that is not part of the returned array.

Returns:

The designated array without the elements before and at the designated index.